Bomar Hatch and GE UltraGlaze
Moderator: Jim Walsh
Bomar Hatch and GE UltraGlaze
Tomorrow I am going to remove the Lexan from my leaking Bomar hatch and re-bed it with GE UltraGlaze. What is a good solvent to use to prep the surface and to clean up, and should I tighten the screws down all the way as soon as I re-install the Lexan?
As I recall, Bomar and/or GE specify isopropyl alcohol for a solvent. Be careful here. Some solvents (i.e., acetone) will melt Lexan.
What screws? The adhesive is supposed to be the only thing attaching the Lexan to the hatch. If a prior owner drilled holes in your Lexan, I would wait for the adhesive to cure and then treat the screws as decorative. Actually, I would get a new piece of Lexan, but you probably don't want to hear that.
What screws? The adhesive is supposed to be the only thing attaching the Lexan to the hatch. If a prior owner drilled holes in your Lexan, I would wait for the adhesive to cure and then treat the screws as decorative. Actually, I would get a new piece of Lexan, but you probably don't want to hear that.
-
Roger McManus
- Posts: 10
- Joined: Feb 14th, '05, 20:50
- Location: Boat: s/v "Cocos"CD 28' Sloop, Hull #71 Annapolis, Maryland
Screws in the Hatch Lens
My 76 CD 28 also has screws in the lens.
-
Ray Garcia
- Posts: 258
- Joined: Apr 27th, '05, 22:08
- Location: 1981 CD27 #212 "Spirit" Huntington, NY
- Contact:
I had the hatch sandblasted and powder coated for less than $70. The lexan was $20 and I had to round over the edge a bit with a router. I replaced the dark lexan with a green tint clear lexan. Let's more light in the v-berth. Not everyone's cup of tea but I like it.
Keeping everything clean is a must. Make sure all the old sealant is removed as best as possible. Use alcohol to clean the frame before starting.
The hardest part of this task is knowing how much UG (Ultra Glaze) to put on. My first try I went too conservative and was not happy with the contact. I had to wipe down the entire hatch and start over. It was messy to say the least.
Get a small can of some mineral spirits. You can get it from the big orange place or your local hardware store has it.
Here is what I did...
Do not rush the job; slow, methodical and carefully works best here for a good result.
Assemble rags (more the better), paper towel, nitril/latex gloves, small plastic spatula, and masking tape.
Tape off all the areas you do not want to get the UG (Ultra Glaze) on. Topside and underneath. Easier to remove the tape later than scrub to get off the excess UG.
I placed the lexan on the hatch and flipped the hatch over to trace a rough outline of where the cross supports are located. I added about 1/2" and carefully removed the paper backing leaving 3 large patches of paper to protect the lexan in case the UG got out of hand. I removed the entire top protective paper. I used 2 pieces of tape to make handles to lower the lexan in place.
Cut the UG tube to give you a 1/4" or better bead. Bigger is better in this case.
Put on the gloves and prepare to get messy. Old newspaper keeps the screaming down to a mild roar. FYI - send the 1st Mate shopping if you plan on working on the dining room table.
I ran a continuous bead around the perimeter and then did the cross members. Don't be afraid to put the stuff on there but don't go crazy either.
Carefully place the lexan on the frame and gently, evenly apply pressure to the lexan. You can gently wiggle the lexan a small bit to evenly disperse the UG.
Don't worry about the squeeze out on top. Roughly clean the top squeeze out then flip the hatch over. Carefully use the small spatula edge to clean up the squeeze out. Use the mineral spirits sparingly if you need to further clean the excess. Once satisfied with the result slowly flip the hatch over again.
Examine the lexan to make sure you have a good seal with the UG on the frame. The edges are more important than the cross members. Though aesthetically an even layer of UG on the cross members is desirable.
On the top I had to add some UG to create a good seal between the frame and the edge of the lexan. Smooth the UG with the spatula or old credit/gift card edge and clean off the excess.
Protect to top of the lexan with some paper towel or newspaper. Place a couple of heavy books to keep the lexan in place and carefully place the frame in an area to be kept undisturbed until the UG sets up and completely cures. 5 days in a reasonably warm place should do the trick. I placed a small bead on a piece of paper as a control to check on the progress of curing.
Carefully remove the tape, you may need to use a razor blade to cut through any areas you missed on cleanup.
Enjoy the new hatch, job well done.
Keeping everything clean is a must. Make sure all the old sealant is removed as best as possible. Use alcohol to clean the frame before starting.
The hardest part of this task is knowing how much UG (Ultra Glaze) to put on. My first try I went too conservative and was not happy with the contact. I had to wipe down the entire hatch and start over. It was messy to say the least.
Get a small can of some mineral spirits. You can get it from the big orange place or your local hardware store has it.
Here is what I did...
Do not rush the job; slow, methodical and carefully works best here for a good result.
Assemble rags (more the better), paper towel, nitril/latex gloves, small plastic spatula, and masking tape.
Tape off all the areas you do not want to get the UG (Ultra Glaze) on. Topside and underneath. Easier to remove the tape later than scrub to get off the excess UG.
I placed the lexan on the hatch and flipped the hatch over to trace a rough outline of where the cross supports are located. I added about 1/2" and carefully removed the paper backing leaving 3 large patches of paper to protect the lexan in case the UG got out of hand. I removed the entire top protective paper. I used 2 pieces of tape to make handles to lower the lexan in place.
Cut the UG tube to give you a 1/4" or better bead. Bigger is better in this case.
Put on the gloves and prepare to get messy. Old newspaper keeps the screaming down to a mild roar. FYI - send the 1st Mate shopping if you plan on working on the dining room table.
I ran a continuous bead around the perimeter and then did the cross members. Don't be afraid to put the stuff on there but don't go crazy either.
Carefully place the lexan on the frame and gently, evenly apply pressure to the lexan. You can gently wiggle the lexan a small bit to evenly disperse the UG.
Don't worry about the squeeze out on top. Roughly clean the top squeeze out then flip the hatch over. Carefully use the small spatula edge to clean up the squeeze out. Use the mineral spirits sparingly if you need to further clean the excess. Once satisfied with the result slowly flip the hatch over again.
Examine the lexan to make sure you have a good seal with the UG on the frame. The edges are more important than the cross members. Though aesthetically an even layer of UG on the cross members is desirable.
On the top I had to add some UG to create a good seal between the frame and the edge of the lexan. Smooth the UG with the spatula or old credit/gift card edge and clean off the excess.
Protect to top of the lexan with some paper towel or newspaper. Place a couple of heavy books to keep the lexan in place and carefully place the frame in an area to be kept undisturbed until the UG sets up and completely cures. 5 days in a reasonably warm place should do the trick. I placed a small bead on a piece of paper as a control to check on the progress of curing.
Carefully remove the tape, you may need to use a razor blade to cut through any areas you missed on cleanup.
Enjoy the new hatch, job well done.
I replaced mine 5 years ago and used the recomended Ultra Glaze without screws as the company directed.........all is well........so far.
________
Mazda 121 history
________
Mazda 121 history
Last edited by Ron M. on Feb 11th, '11, 06:08, edited 1 time in total.
-
Maine Sail
- Posts: 839
- Joined: Feb 8th, '06, 18:30
- Location: Canadian Sailcraft 36T
If using
If using Lexan/Polycarbonate be sure that you have the Bomar 100 series hatches with the reinforcement cross bars.
They would look like this:
If your Bomar hatch does not have the cross bars you'll want to use cast acrylic as Bomar does on non-cross bar hatches. Lexan, while highly impact resistant, flexixes and foreshortens much more easily than cast acrylic. Without cross members green water or an errant misstep could break the seal by flexing the Lexan or worse force the entire lens into the cabin. Bomar, as far as I can recall only uses the Lexan on the cast aluminum 100 series hatches with cross bracing..
Here are some quotes from Tony D'andrea who is the Acrylic & Polycarb guru in the marine industry. He is the Nigel Calder of portlights and hatches and owns the largest hatch warranty & repair facility in the world Select Plastics..
Tony on Acrylic vs. Polycarbonate:
"Consider the Following:
* All major hatch, portlight and window manufacturers use Acrylic in offshore / bluewater marine products.
* Acrylic is more scratch resistant than standard (9034) polycarbonate.
* Acrylic is significantly more durable when exposed to Ultra Violet radiation (sunlight).
* Acrylic is less expensive than Polycarbonate.
Don't misunderstand my preference for acrylic. I buy, use and sell a significant amount of both products and each has its application. In my humble opinion Acrylic is more durable, versatile and cost effective in the hands of a skilled craftsman than polycarbonate.
Additional considerations may include polycarbonate with UV and scratch resistant coatings. While these products are heavily promoted by several manufacturers and carry 5, 10 even 15 year warranties the following information has been reported in "real life"applications:
* Polycarbonate is impact resistant. When its new it is almost impossible to break.
* Small quantities (less than a 4 by 8) in gauges over 1/8th inch are difficult to to find in the uv/scratch resistant grades.
* Colors are limited. Only two standards (gray and bronze). Try and find anything thicker than 1/4 in UV/ scratch resistant!
* Polycarbonate foreshortens when subject to static or dynamic loads. What this means is if you replace your hatch lens with polycarb, seal it and then step on it the ductile material will deflect (bow) in the center. One of two things may happen. 1st you will surely break the watertight seal, 2nd you may end up with a leg in your galley.
* As for the warranty: The original owner is warranted against failure subject to the material being submitted to the distributor for evaluation with the original invoice subject to actual replacement cost at the time of purchase. I guess this means they sell you a new square of material and apply the old payment to the new cost. How about the labor to fabricate the part, install it and sealant? Why take the chance?
Polycarbonate is a great material, The US Air force uses it for fighter canopies! I sell Polycarb to the USCG and US Navy. Remember they don't mind using it because we are paying to replace it every three years.
Both Acrylic and Polycarbonate have specific uses and installation requirements.
Cast Acrylic (of a specific thickness) is in accordance with CE and ABYC guidelines, and installed on virtually all of the big blue water sail boats produced on both sides of the pond. Polycarbonate is commonly used as a replacement due to its ease of fabrication and incredible initial strength. The USCG and USN require Polycarbonate on their vessels but they also have a PM cycle of 36 to 42 months for change out. My Tax dollars at work...
Due to its ductility Polycarbonate it is more challenging to install. I have seen Sika Flex 295UV with primer and Dow 795 both mentioned. I use and recommend both. Dont go over 4 ft continuous length with a fixed portlight. Remember the coefficiant of thermal expansion for Acrylic and Polycarbonate is in the neiborhood of .000039 per inch per degree F. That means an 8ft plastic port will expand and contract up to 1/2 of an inch from the coldest day in Feb to the hottest day in summer. WOW!! Compartmentalize the job. It will be easier to install and less prone to leaks.
Never ever bolt a plastic portlight in place. Screws are fine to hold a lens till the adhesive cures. Take them out asap and fill the holes with the afformentioned products. Both of these products are rated at 700 + percent elongation before tear. Strong flexible and UV resistant.
Been to a boat show lately? Seen any screws? Glass is good so long as your boat does not twist or torque. Show me a fiberglass boat that does not twist and I will show you a cocktail barge tied to the dock."
Tony on Sealants:
"I hear the question as to which sealant to use when bonding Acrylic, or Polycarbonate to aluminum, stainless or FRP over and over and over.....
Well here goes... The only three adhesives I would consider using are Sika Flex 295 UV with the primer, GE SSG-4000, and Dow 795. Using the correct adhesive is only 1/2 the battle. Do not apply the sealants below 50 degrees F. The temperature must maintain at least 50F during the entire 21 day cure cycle. Cut this corner and your finished before you start. Preparation of the bond area is also very/ very important. DO NOT TOUCH THE BOND AREA WITH YOUR BARE HANDS! Contamination from the dirt and skin oils will make a solid cure impossible. You may clean the FRP and metal with acetone to prep the area but if you touch the Lexan or Plexi with harsh solvents you will ruin the portlight. A 50/50 mix of isopropal alcohol and distilled water will work well to clean the plastic if needed. Remember that clean enough is not clean enough."
Those are not my words they are the words of one of the most experienced marine plastics guys on the planet..
They would look like this:
If your Bomar hatch does not have the cross bars you'll want to use cast acrylic as Bomar does on non-cross bar hatches. Lexan, while highly impact resistant, flexixes and foreshortens much more easily than cast acrylic. Without cross members green water or an errant misstep could break the seal by flexing the Lexan or worse force the entire lens into the cabin. Bomar, as far as I can recall only uses the Lexan on the cast aluminum 100 series hatches with cross bracing..
Here are some quotes from Tony D'andrea who is the Acrylic & Polycarb guru in the marine industry. He is the Nigel Calder of portlights and hatches and owns the largest hatch warranty & repair facility in the world Select Plastics..
Tony on Acrylic vs. Polycarbonate:
"Consider the Following:
* All major hatch, portlight and window manufacturers use Acrylic in offshore / bluewater marine products.
* Acrylic is more scratch resistant than standard (9034) polycarbonate.
* Acrylic is significantly more durable when exposed to Ultra Violet radiation (sunlight).
* Acrylic is less expensive than Polycarbonate.
Don't misunderstand my preference for acrylic. I buy, use and sell a significant amount of both products and each has its application. In my humble opinion Acrylic is more durable, versatile and cost effective in the hands of a skilled craftsman than polycarbonate.
Additional considerations may include polycarbonate with UV and scratch resistant coatings. While these products are heavily promoted by several manufacturers and carry 5, 10 even 15 year warranties the following information has been reported in "real life"applications:
* Polycarbonate is impact resistant. When its new it is almost impossible to break.
* Small quantities (less than a 4 by 8) in gauges over 1/8th inch are difficult to to find in the uv/scratch resistant grades.
* Colors are limited. Only two standards (gray and bronze). Try and find anything thicker than 1/4 in UV/ scratch resistant!
* Polycarbonate foreshortens when subject to static or dynamic loads. What this means is if you replace your hatch lens with polycarb, seal it and then step on it the ductile material will deflect (bow) in the center. One of two things may happen. 1st you will surely break the watertight seal, 2nd you may end up with a leg in your galley.
* As for the warranty: The original owner is warranted against failure subject to the material being submitted to the distributor for evaluation with the original invoice subject to actual replacement cost at the time of purchase. I guess this means they sell you a new square of material and apply the old payment to the new cost. How about the labor to fabricate the part, install it and sealant? Why take the chance?
Polycarbonate is a great material, The US Air force uses it for fighter canopies! I sell Polycarb to the USCG and US Navy. Remember they don't mind using it because we are paying to replace it every three years.
Both Acrylic and Polycarbonate have specific uses and installation requirements.
Cast Acrylic (of a specific thickness) is in accordance with CE and ABYC guidelines, and installed on virtually all of the big blue water sail boats produced on both sides of the pond. Polycarbonate is commonly used as a replacement due to its ease of fabrication and incredible initial strength. The USCG and USN require Polycarbonate on their vessels but they also have a PM cycle of 36 to 42 months for change out. My Tax dollars at work...
Due to its ductility Polycarbonate it is more challenging to install. I have seen Sika Flex 295UV with primer and Dow 795 both mentioned. I use and recommend both. Dont go over 4 ft continuous length with a fixed portlight. Remember the coefficiant of thermal expansion for Acrylic and Polycarbonate is in the neiborhood of .000039 per inch per degree F. That means an 8ft plastic port will expand and contract up to 1/2 of an inch from the coldest day in Feb to the hottest day in summer. WOW!! Compartmentalize the job. It will be easier to install and less prone to leaks.
Never ever bolt a plastic portlight in place. Screws are fine to hold a lens till the adhesive cures. Take them out asap and fill the holes with the afformentioned products. Both of these products are rated at 700 + percent elongation before tear. Strong flexible and UV resistant.
Been to a boat show lately? Seen any screws? Glass is good so long as your boat does not twist or torque. Show me a fiberglass boat that does not twist and I will show you a cocktail barge tied to the dock."
Tony on Sealants:
"I hear the question as to which sealant to use when bonding Acrylic, or Polycarbonate to aluminum, stainless or FRP over and over and over.....
Well here goes... The only three adhesives I would consider using are Sika Flex 295 UV with the primer, GE SSG-4000, and Dow 795. Using the correct adhesive is only 1/2 the battle. Do not apply the sealants below 50 degrees F. The temperature must maintain at least 50F during the entire 21 day cure cycle. Cut this corner and your finished before you start. Preparation of the bond area is also very/ very important. DO NOT TOUCH THE BOND AREA WITH YOUR BARE HANDS! Contamination from the dirt and skin oils will make a solid cure impossible. You may clean the FRP and metal with acetone to prep the area but if you touch the Lexan or Plexi with harsh solvents you will ruin the portlight. A 50/50 mix of isopropal alcohol and distilled water will work well to clean the plastic if needed. Remember that clean enough is not clean enough."
Those are not my words they are the words of one of the most experienced marine plastics guys on the planet..